Portions of the UVES spectrum (black squares) around the subordinate and resonance Li lines (the upper panel and the middle and lower panels, respectively). In the upper panel, the observed spectrum is superimposed onto the best-fit synthetic spectrum (thick red line) and two synthetic spectra calculated with ±0.1 dex with respect to the best-fit one (thin red lines), assuming ⁶Li∕⁷Li = 0.00. Middle panels: the observed spectrum is compared with a set of synthetic spectra calculated with the best-fit abundance (thick line) and ±0.1 dex with respect to the latter (thin lines), assuming ⁶Li∕⁷Li = 0.00 and 0.08 (left and right panels, respectively). Lower panels: residuals between the observed spectrum and the synthetic spectra shown in the above panels.